EFFECTS OF UREAPLASMA-DIVERSUM ON BOVINE OVIDUCTAL EXPLANTS - QUANTITATIVE MEASUREMENT USING A CALMODULIN ASSAY

Calmodulin (CAM) acts as an intracellular regulator of calcium, an imp ortant mediator of many cell processes. We used the CAM assay and elec tron microscopy to investigate the effects of Ureaplasma diversum on b ovine oviductal explants obtained aseptically from slaughtered cows. A stock suspension of U. diversum (treated specimens) and sterile broth (controls) was added to replicates of cultured explants and incubated at 38 degrees C in an atmosphere of 5.5% CO2 for 48 hours. Explants w ere examined for ciliary activity, extracellular CAM loss, and for his tological and ultrastructural changes. Explants and their culture medi a were examined for changes in CAM concentration. All experiments were replicated three times. In addition, U. diversum, medium and broth we re assayed for CAM content. The concentrations of CAM in explants and media changed significantly (p < 0.05) in samples which were inoculate d with U. diversum when compared to controls. The controls and infecte d specimens did not differ histologically or ultrastructurally, but U. diversum was seen to be closely associated with infected explant tiss ue. In view of this close affinity it is assumed the loss of CAM from the oviductal cells was causally related, but this was not proven. The failure to show cell membrane injury on light and electron microscopi c examination was probably related to the short duration of the experi ment and may only point out the sensitivity of the CAM assay in detect ing early cell membrane injury. Compromise in characteristics of the m edium to support both, the viability of oviductal cells and U. diversu m limited the experimental time to 48 hours. Further work is necessary to develop a medium which allows for longer explant exposure. Membran e injury in oviductal and uterine cells may be a contributing factor i n early reproductive failure associated with U. diversum infection in cattle.